CN104220780A

CN104220780A - Tensioner and endless drive arrangement

Info

Publication number: CN104220780A
Application number: CN201280072082.XA
Authority: CN
Inventors: 鲍里斯·雷普莱特; 罗恩·法雷韦尔; 安德鲁·博耶斯; 英戈·巴茨; 约恩·亚当
Original assignee: Litens Automotive Partnership
Current assignee: Litens Automotive Partnership; Litens Automotive Inc
Priority date: 2012-03-29
Filing date: 2012-11-09
Publication date: 2014-12-17
Anticipated expiration: 2032-11-09
Also published as: CN104220780B; US20150051033A1; EP2831468A1; WO2013142951A1; EP2831468B1; US9341243B2; EP2831468A4

Abstract

In one aspect, a tensioner is provided, comprising, a first tensioner arm and a second tensioner arm, a first wheel and a second wheel. The first tensioner arm is pivotable about a first pivot axis. The second tensioner arm is pivotally connected to the first arm so as to be pivotable about a second pivot axis located at a selected distance from the first pivot axis. The first wheel is rotationally connected to the first tensioner arm about a first rotation axis. The second wheel is rotationally connected to the second tensioner arm about a second rotation axis. The first and second wheels are configured to engage an endless drive member. The first and second wheels are biased in respective first and second free arm directions.

Description

Stretcher and annular gear

The cross reference of related application

This application claims the U.S. Patent application No.13/434 submitted on March 29th, 2012,787, in the U.S. Provisional Patent Application No.61/645 that on May 10th, 2012 submits to, 052, in the U.S. Provisional Patent Application No.61/655 that on June 4th, 2012 submits to, 474 and on September 11st, 2012 submit to U.S. Provisional Patent Application No.61/699, the rights and interests of 694, the full content of all above-mentioned patent applications is incorporated to herein by reference.

Technical field

The disclosure relates generally to the field of the stretcher for annular gear, and more particularly, relates to the belt driver of the starter motor-generator unit for using Y type stretcher.

Background technique

Since generation nineteen ninety, ever-increasing many motors with starter motor-generator unit are developed to improve fuel mileage.In such engines, when vehicle stops mobile such as, when red light, combustion process stops.In this case, starter generator unit operates as starter motor to reset motor.Once engine start, starter motor-generator unit can optionally as generator operation with to battery recharge.

Starter generator unit is such as with by annular gear or chain is mechanically connected to motor.Endless drive be subject to tensioning fluctuation, particularly when starter motor-generator unit changes its function between starter motor and generator, in this case, endless drive tighten up side and slack-side is put upside down.This and other tensionings fluctuation that endless drive clamping system occurs when must process power operation.

Various dual arm tensioner is as known in the art, and the example of this dual arm tensioner sees publication number DE 102 53 450 A1, EP 1 464 871 A1, US 2004/0171448 A1, EP 1 122 464 A1 and DE 42 43 451 A1.But, stretcher disclosed herein seek to provide a kind of more firm solution with in the part of effective compensation endless drive because of vertical shift that the conversion of tightening up between side and slack-side occurs.

Summary of the invention

On the one hand, provide a kind of stretcher, this stretcher comprises the first tensioner arms, the second tensioner arms, the first round and second take turns.First tensioner arms can around the first pivot axis.Second tensioner arms is connected to the first arm pivotly thus can around the second pivot axis be positioned to apart from the first pivot axis selected distance.The first round is connected to the first tensioner arms in the mode rotated around the first spin axis.Second takes turns to be connected to the second tensioner arms around the mode of the second spin axis rotation.The first round becomes engagement annular dirivig member with the second wheel construction.The first round and second takes turns and is biased along corresponding first free arm and the second free arm direction.

On the other hand, the annular gear being combined with endless drive component as above and stretcher is provided.

Accompanying drawing explanation

With reference to the accompanying drawings, foregoing and other aspect will be easier to understand, in the accompanying drawings:

Fig. 1 is the plan view of the mode of execution of stretcher;

Fig. 2 is the stereogram of the stretcher shown in Fig. 1;

Fig. 3 is the sectional view of the stretcher along the line III-III intercepting shown in Fig. 2;

Fig. 4 stretcher shown in Fig. 1 shown in starter motor-generator belt driver is in the model of initial quasistatic position;

Fig. 5 shows the model being in the stretcher of primary importance in the belt driver of Fig. 4, and in primary importance, starter motor-generator operates as starter motor;

Fig. 6 shows the model being in the stretcher of the second place in the belt driver of Fig. 4, and starter motor-generator is as generator operation in the second position;

Fig. 7 shows the torque characteristics of starter motor-generator unit;

Fig. 8 is the stereogram of another mode of execution of stretcher;

Fig. 9 a is the stereogram of a part for the stretcher shown in Fig. 8;

Fig. 9 b is the exploded view of the stretcher shown in Fig. 8;

Figure 10 is the planimetric map of the stretcher shown in Fig. 8;

Figure 11 a to Figure 11 j is the planar elevation view that can be used as the substituting biasing member of a part for the stretcher shown in Fig. 8;

Figure 12 is the planimetric map of the stretcher shown in Fig. 8, but each tensioner arms in two tensioner arms has biasing member;

Figure 13 a to Figure 13 d shows the cross sectional elevation of the damping structure of the apolegamy of the first tensioner arms for suppressing the stretcher shown in Fig. 8;

Figure 14 shows the front view of the damping structure of the apolegamy of the second tensioner arms for suppressing the stretcher shown in Fig. 8;

Figure 15 shows the planimetric map of the modification of the stretcher shown in Fig. 8;

Figure 16 shows the exploded perspective view of the limiting structure of the stroke range of the first tensioner arms for limiting the stretcher shown in Fig. 8;

Figure 17 shows the exploded perspective view of the limiting structure of the stroke range of the second tensioner arms for limiting the stretcher shown in Fig. 8;

Figure 18 to Figure 20 is the planimetric map of the alternative location of the idle pulley/lazy belt wheel that can be provided with the stretcher shown in Fig. 8; And

Figure 21 is the planimetric map of another idle pulley for engaging with the second endless drive component that can be provided with the stretcher shown in Fig. 8.

Embodiment

Fig. 1 is the plan view that can be used for mode of execution endless drive component 54 (Fig. 4) being carried out to the stretcher 1 of tensioning.Stretcher 1 comprises the first tension arms 2 (can be called as main tensioner arms) and the second tension arms 3 (can be called as secondary tensioner arms).First tension arms 2 is mounted to construction element pivotly---such as with the engine cylinder-body that 99 (Fig. 4) illustrate, for carrying out pivot movement around the first pivot axis 4.Second tension arms 3 is hinged to the first tension arms 2 and makes it possible to around the second pivot axis 5 pivotable.First tension arms 2 support can around first spin axis 7 rotate the first Idle wheel 6 and second tension arms 3 support can around second spin axis 9 rotate the second Idle wheel 8.Second tension arms 3 is biased along the second free arm direction by the stretcher spring 38 (Fig. 3) extended between the second arm 3 and the first arm 2.This spring can also be regarded as making the first arm 2 (with the first belt wheel 6) biased along the first free arm direction.Usually, free arm direction is the direction that arm 2 or 3 will be advanced when its motion is not resisted by band 54.In the illustrated embodiment, arm 2 and arm 3 will move towards each other when moving along free arm direction.That load stops direction in the opposite direction with free arm side.This is that arm 2 or 3 is urged and the direction of movement by band 54.

Second pivot axis 5 is positioned to a certain distance of distance the first pivot axis 4, that is, the second pivot axis is eccentric relative to the first pivot axis.More particularly, the position of the second pivot axis 5 is preferably departed from from the line AA between the first pivot axis 4 and the first spin axis 7 with from the line BB between the second pivot axis 5 and the second spin axis 9.

Idle wheel 6,8 can be the form of belt wheel, and endless drive component 54 can in the form of band, such as V-type band (only as an example of suitable asynchronous band).In the whole disclosure, term " belt wheel " can use about wheel 6 and 8, and term " band " can use about endless drive component 54, but it should be noted that these terms only to use and they are only as the example of the type of the endless drive component that can use alternatively and wheel for convenience.Such as, endless drive component 54 can be chain or toothed belt or some other forms of endless drive components, and to take turns 6 and 8 can be the wheel of sprocket wheel, profile of tooth belt wheel or any other type alternatively.

Distance D1 between first pivot axis 4 and the second pivot axis 5 is 1/4 of the distance D3 of distance D2 between the second pivot axis 5 and the first spin axis 7 and/or the second pivot axis 5 to the second spin axis 9.Preferably, the distance D1 between the first pivot axis 4 and the second pivot axis 5 is that 1/3 of the distance D3 of distance D2 between the second pivot axis 5 and the first spin axis 7 and/or the second pivot axis 5 to the second spin axis 9 is more preferably at least half.Advantageously, the distance D1 between the first pivot axis 4 with the second pivot axis 5 can also be chosen as and the distance D3 of distance D2 between the second pivot axis 5 and the first spin axis 7 and/or the second pivot axis 5 to the second spin axis 9 approximate equally large.In this illustrative embodiments, the second pivot axis 5 is arranged to distance the first pivot axis 4, first spin axis 7 and the approximately equalised distance of the second spin axis 9, that is, D1, D2 and D3 are approximately uniform.

Distance D1 between first pivot axis 4 and the second pivot axis 5 is larger, and the distance D2 between the second pivot axis 5 and the first spin axis 7 and distance D3 between the second pivot axis 5 and the second spin axis 9 is less.The First Line 11 connecting the second pivot axis 5 and the first spin axis 7 can be chosen as suitably larger with the subtended angle be connected between the second pivot axis 5 and the line 12 of the second spin axis 9, particularly when tensioning pulley 6,8 is otherwise in identical position.

This subtended angle 10 can remain in the scope of such as 60 degree to 90 degree.Subtended angle is larger, first jiao of 13a (see Fig. 4) between the first hub load force introduced by the first tensioning pulley 6 and the First Line 11 angle α of line AA (or relative to) is less, and second jiao 15 (see Fig. 4) between the second hub load force introduced by the second tensioning pulley 8 and the second line 12 angle β of line BB (or relative to) is less.First jiao 13 and second jiao 15 (or α and β) less, as tensile force by discussed tension arms absorb corresponding resultant force component larger.Therefore, tension arms 2,3 spring force carried out needed for tensioning is become less.When subtended angle 10 be in 60 degree to 90 degree of scopes, it is also even like this when belt tension sharply increases because of the operation of belt driver that tension arms is not opened so significantly.In other words, the cornerite of belt wheel---its section is tensioned by stretcher 1---does not diminish sharp.

However,---such as tightening up the transition period between side and slack-side---can be compensated by means of the distance D1 between the first pivot axis 4 such as selected by mode of execution and the second pivot axis 5 effectively by stretcher 1 to occur in the vertical shift in band.

In this illustrative embodiments, First Line 11 and the 3rd line 17 being connected the first pivot axis 4 and the second pivot axis 5 form preferably 140 degree of obtuse angles 18 (see Fig. 1) to 175 degree of scopes.Therefore, compared with the stretching, extension form of the first tension arms 2, the length of the second tension arms 3 can be reduced, and therefore, larger the opening of subtended angle 10 is possible, particularly when tensioning pulley 6,8 is otherwise in same position.In addition, this is of value to the good cornerite of maintenance and allows reduction further to carry out the power needed for tensioning to two tension armss 2,3.

But, the angle 18 being greater than 175 degree or the even angle of 180 degree also can be provided between First Line 11 and the 3rd line 17.In other embodiments, on the both sides of the second tensioning pulley 8,140 degree to 175 degree or larger angle can also be provided between the 3rd line 17 and First Line 11.In a word, the angle 18 between First Line 11 and the 3rd line 17 can in the scope of 180 degree of +/-40 degree.

Fig. 2 is the stereogram of stretcher 1.To can be clearly seen that in the region being contained in the second pivot axis 5 and less installing space is occupied to the spring that tension arms 2 and 3 carries out tensioning.Thus, less for the spring force needed for tensioning object, required spring self is more weak, and the installing space of needs is then less.In other words, the design of the stretcher 1 of preferred implementation suggestion and the reduction of the tension force of needs that causes also cause the reduction of structural volume.

Fig. 3 is the sectional view of the stretcher 1 that the line III-III indicated along Fig. 2 intercepts.This stretcher 1 can be arranged on such as explosive motor by means of mounting screw 19, and wherein, mounting screw 19 extends through bearing bolt 20---and substrate 21 is arranged on bearing bolt 20 integratedly.Bearing bolt 20 extends through the bearing eye 22 of the first tension arms 2.Bearing bolt 20 further extends through header board 24 on head 23 side of mounting screw 19.On the opposite side, bearing bolt 20 additionally extends through by stacked disc spring 25 on the base plate (21 and extends through the extruding disk 26 leaned against on stacked disc spring 25.Between bearing eye 22 and bearing bolt 20, be provided with bearing sleeve 27, this bearing sleeve 27 has the flange 28,29 extended radially outwardly at its opposite end place.Bearing sleeve 27 is one single piece in embodiments, but it also can be two-piece type.

Bearing sleeve 27 has dual functions.First, bearing sleeve 27 supports the first tension arms 2 and makes it rotate freely.Secondly, bearing sleeve 27 suppresses the rotary motion of the first tension arms 2 by means of frictional damping.More particularly, frictional damping produces by means of two flanges 28,29, stacked disc spring 25 makes the friction cooperation parts of flange 28,29 be pressed against on flange 28,29, and these friction cooperation parts are header board 24 and bearing eye 22 on the one hand, and is extruding disk 26 and bearing eye 22 on the other hand.

What can also be provided for bearing sleeve 27 such as can the damping tray of separation in Furtulon Coated Steels disk-form, substituting as flange 28,29, such as, shown in U.S. Patent Publication No.2008/0280713 and D.B.P. no.DE1952 4403.

First tension arms can rotate freely around the first pivot axis 4, namely there is not spring and is biased.

First tension arms 2 comprises the spring housing 30 of roughly cup-shaped.The second bearing bolt 32 is extended with integratedly from the base portion 31 of spring housing.Second bearing bolt 32 extends through the bearing eye 33 of the second tension arms 3.Between bearing eye 33 and the second bearing bolt 32, be provided with the second bearing sleeve 34, second tension arms 3 to be arranged on the second bearing bolt 32 by means of the second bearing sleeve 34 thus the second tension arms 3 is rotated freely.Comprise and extending radially outwardly from the bearing eye 33 of the second tension arms 3 towards the spring cup 35 in the axially outstanding eckband portion 36 of base portion 31.Bearing eye 33 and overcome stretcher spring 38 (such as by the second header board 37 with the spring cup 35 that bearing eye 33 is integrally formed, can be the spring of spirally winding torsion spring as shown in Figure 3 or any other suitable type, such as below about the spring described by Figure 11 a to Figure 11 j) axial force and be axially fixed on the second bearing bolt 32.

In the present embodiment, the cylindrical shape of the second bearing bolt 32.Alternatively, the conical bearing along leaving the direction convergent that base portion 31 extends can also be provided.To provide along leaving the bearing sleeve of the direction convergent that base portion 31 extends with alternative hollow circle tube second bearing housing 34 subsequently, and the direction convergent that base portion 31 extends is left on same edge by the inner peripheral surface corresponding with the outer peripheral surface of this bearing sleeve of bearing eye.The example of such structure sees U.S. Patent No. 4,698,049.

Wind spring/wind spring 38 pairs of tension armss 2,3 load in mode toward each other.Push more by force tension arms 2,3 open by band power, it is larger that the diameter of wind spring 38 reduces.Therefore, wind spring strongly holds the damping bushing 40 of the band notch be arranged between wind spring and the axial extension part 39 of bearing eye 33.In other words, wind spring 38 adds following power: damping bushing 40 is rubbed by this power the bearing eye 33 of the second tension arms 3, more particularly rubs on the axial extension part 39 of bearing eye 33, therefore makes damping force increase.For the bottom 41 providing wind spring 38 for the flange 42 extended radially outwardly rotated with it of damping bushing 40.

Alternatively, spring 38 can be arranged to the spring 38 when tension arms 2,3 is open by band power and widen diametrically.Then damping bushing can be provided with between wind spring and the cylindrical wall 43 of spring housing 30, and described damping bushing can rotate relative to cylindrical wall 43 when tension arms is pivoted relative to each other and rub on cylindrical wall 43.The example of such structure sees U.S. Patent No. 8,142,314, and its full content is incorporated to herein by reference.

Fig. 4 to Fig. 6 shows the simulation model of the simulation model of exemplary belt driver 50 and the preferred stretcher 1 under being in variant serviceability.Such as, belt driver comprises crankshaft pulley 51, the belt wheel 52 of starter motor-generator unit and additional belt wheel 53, and wherein, this crankshaft pulley 51 is connected to the bent axle of explosive motor, and additional belt wheel 53 can be connected to such as air condition compressor.In this example, starter motor-generator unit is generator for generation of electricity and it can also be operating as the electric motor for piloting engine.Fig. 7 schematically shows the typical torque curve about conventional starter motor-generator unit, according to this curve, it should be understood that, when this unit is as time motor operated, Peak torque on belt wheel 52 is quite high, and when this unit is as generator operation, the Peak torque on belt wheel 52 is relatively low.

As shown in Figure 4, strip winding wheel is provided with band 54 in the paths.In mode of execution in the diagram, band 54 is tensioned by the first tensioning pulley 6 and the second tensioning pulley 8, wherein, first tensioning pulley 6 rests against the first band portion section 55 extended between crankshaft pulley 51 and the belt wheel 52 (can be called as SGU belt wheel 52) of starter motor-generator unit, and the second tensioning pulley 8 rests against the second band portion section 56 extended between SGU belt wheel 52 and the belt wheel 53 (can be called as a/c compressor belt wheel 53) of air condition compressor.Tensioning pulley 6,8 is pressed against band portion section 55,56 from outside.

In the diagram, stretcher 1 is in tensioning initial position.Motor is in running and the generator load of starter motor-generator unit is zero, that is, system is in quasistatic state.Notice that in this condition, hub load force 58 (load on the axle of belt wheel 52) roughly carries out orientation along the line through the first pivot axis 4.

When adopting the propulsion functions of starter motor-generator unit so that when additionally driving crank is to pilot engine, starter motor-generator unit must pull motor by means of crankshaft pulley 51.First band portion section 55 becomes tightens up side and it is tensioned.By contrast, the second band portion section 56 becomes slack-side and it relieves tensioning.Usually, when portion's section of band 54 be called as tighten up side and with portion's section be called as slack-side time, should notice that these terms are relative to each other.In other words, when second section 56 of endless drive component 54 is " tightening up side ", this means that second section 56 is subject to the tensioning higher than first section 55, and when first section 55 of endless drive component 54 is " tightening up side ", first section 55 is subject to the tensioning higher than second section 56.

First band portion section 55 around the vertical shift formed of the first pivot axis 4 towards the first band portion section 55 pivotable and thus compensating band portion section, that is, to shorten and by the lengthening of the second band portion section 56 by stretcher 1.After pivot movement, stretcher 1 is in the position being different from the initial position shown in Fig. 4 as observed in Fig. 5.In this illustrative embodiments, the first hub load force 14 on the first belt wheel 6 and between First Line 11 first jiao 13 are reduced to the value being less than 30 degree, are even less than the value of 25 degree.Similarly, the angle [alpha] between power 14 and line AA reduces.Thus, the first hub load force 14 is main/and large component absorbs using the form of tensile force by the first tension arms 2 with by the bearing of the part as the first pivot axis 4.Only the first little component of making a concerted effort with the angle effect vertical with First Line 11 or line AA and its must be absorbed by the wind spring 38 two tension armss being carried out to tensioning, the second tension arms 3 is suitably supported against the second band portion section 56 by means of the second tensioning pulley 8 of the second tension arms 3.

The the second hub load force 16 acted on the second tensioning pulley 8 is little and tensioning necessary in the second band portion section 56 is easily kept by wind spring 38.

Compared with the diagram shown in Fig. 4, subtended angle 10 substantially constant.Subtended angle 10 has only slightly opened to be less than 10 degree and to have opened in this illustrative embodiments and has been less than 5 degree.Thus, the cornerite with 54 strip winding wheels 52 keeps the constant power transmission capacity substantially constant made between band 54 and belt wheel 52 substantially.

When motor is started by starter motor-generator unit, there is similar operations state as shown in Figure 5.

Starter motor-generator unit must by means of band 54 by internal combustion engine drives when it is converted to generator mode from starter motor or engine mode.Second band portion section 56 becomes tightens up side and is tensioned.By contrast, the first band portion section 55 becomes slack-side and is removed tensioning.Second band portion section 56 around the vertical shift of the first pivot axis 4 towards the second band portion section 56 pivotable and thus compensating band portion section, that is, shortens and the first band portion section 55 is lengthened by stretcher 1.After completing pivot movement, stretcher 1 reaches the second place being different from the initial position shown in Fig. 4 as observed in Fig. 6.Second hub load force 16 is greater than the first hub load force 14.Be decreased to the value being significantly less than 30 degree for second jiao 15, and be even decreased to the value being less than 20 degree.In the illustrated embodiment, this angle is less than 15 degree.Similarly, compared with Fig. 4, the angle β between power 16 and line BB reduces.Therefore, the orthogonal component around pivot axis 5 reduces, thus for the tendency that given unit power reduction arm 2,3 is opened.In addition, the fundamental component of the second hub load force 16 is by means of the bearing of the part as the second pivot axis 5, introduce the second tension arms 3 and the first tension arms 2 with the form of tensile force.This power is absorbed by the bearing as a part for the first pivot axis 4 on the one hand, and the fact being bearing on the first band portion section 55 due to the first tension arms 2 by means of the first tensioning pulley 6 is on the other hand absorbed.However, the first hub load force 14 is less than the second hub load force 16.Wind spring 38 easily can compensate the orthogonal component of the hub load force 14,16 pushed open by tension arms.

The arranged off-centre of the second pivot axis 5 contributes to this layout, because the fundamental component of the second hub load force 16 is directed along the line BB through the first pivot axis 4 in position.

System shown in Fig. 4 to Fig. 6 mathematically can be understood by the equation of simplification below.

The moment of torsion around pivot axis 4 of the Angle Position of initialization system is generally

\overset{&RightArrow;}{L_{4,7}} \times \overset{&RightArrow;}{F_{14}} + \overset{&RightArrow;}{L_{4,9}} \times \overset{&RightArrow;}{F_{16}} = 0,

Or

L _4,7·F ₁₄·sinα＝L _4,9·F ₁₆·sinβ

Wherein, L _4,7it is the vector between axle 4 and axle 7; L _4,9vector between axle 4 and axle 9.

Determine that the moment of torsion around pivot axis 5 of subtended angle 10 is

\overset{&RightArrow;}{L_{5,9}} \times \overset{&RightArrow;}{F_{16}} = k \cdot (θ_{p} + θ_{10}),

Or

L _5,9·F ₁₆·sinθ ₁₅＝k·(θ _p+θ ₁₀)

Wherein, L _5,9it is the vector between axle 5 and axle 9; θ ₁₀be subtended angle 10 and θ _ppreload angle (when spring transmits preload moment of torsion).

From finding out that subtended angle 10 does not roughly change when stretcher 1 is converted to the second place above.As compared with the serviceability shown in Fig. 5, in this case, subtended angle 10 is less than 5 degree this reducing to be less than 10 degree and even to reduce.This contributes to keeping good cornerite.

The angle that holds of the belt wheel 52 of starter motor-generator unit additionally increases because of the geometrical shape of stretcher and the location of pivot axis 4.First pivot axis 4 is arranged on following position: in this position, the first tensioning pulley 6 reduces the distance of the belt wheel 52 of itself and starter motor-generator unit when stretcher 1 is switched to the second place (Fig. 6) from primary importance (Fig. 5).First spin axis 7 is towards line (not shown in the accompanying drawings) pivotable between the first pivot axis 4 and the spin axis 57 of belt wheel 52.

In addition, the geometrical shape of stretcher can be chosen to make the second spin axis 9 and the distance of pivot axis 4 be slightly less than the distance of the first spin axis 7 and the first pivot axis 4.Thus, when stretcher is switched to the second place, with the second tensioning pulley 8 move the belt wheel 52 leaving starter motor-generator unit degree compared with, the first tensioning pulley 6 is more strongly near the belt wheel 52 of starter motor-generator unit.

In a preferred embodiment, the first tension arms 2 is dispensed to portion's section of the operation period generation maximum belt tensioning at belt driver, that is, the first band portion section 55.Therefore, maximum fundamental component of making a concerted effort introduces the first tension arms 2 and the bearing of the part as the first pivot axis 4 of the device 1 that is tensioned directly absorbs using the form of tensile force.This contributes to the spring force reducing to carry out needed for tensioning to two tension armss equally.

According to foregoing, be understandable that, stretcher as disclosed herein can keep the good cornerite around endless drive wheel by means of tension arms---and wherein tension arms is that spring is biased toward each other, also be even like this in the transition period of tightening up side and slack-side, further, stretcher 1 can by means of the eccentricity effective compensation between the first pivot axis and the second pivot axis with the vertical shift in the some parts of the endless drive of this conversion.In addition, for this stretcher, the basic tensioning of the appropriate level of endless drive can be realized simultaneously.

Stretcher 1 can move between following primary importance and the following second place, wherein, in primary importance, when first section is when tightening up side, first tensioning pulley forms first jiao that is less than 30 degree with the line being connected the second pivot axis and the first spin axis with joint efforts, in the second position, when second section is when tightening up side, the second tensioning pulley forms second jiao that is less than 30 degree with the line being connected the second pivot axis and the second spin axis with joint efforts.Due to following first section be when tightening up side first jiao be less than 30 degree and second section be when tightening up side second jiao be less than the fact of 30 degree, then the described fundamental component of making a concerted effort is absorbed by corresponding tension arms with the form of tensile force.Thus the spring force carried out needed for tensioning two tension armss is less.The basic tensioning level of endless drive reduces due to the tensioned power reduced.

Advantageously, first jiao that is in primary importance and/or second jiao that is in the second place can be less than 25 degree, preferably be less than 20 degree, be even more preferably less than 15 degree.Angle is less, and the component that can be absorbed by above-mentioned tension arms with tensile force form of making a concerted effort is larger.Correspondingly, tensioned power more in a small amount can be used to carry out tensioning for two tension armss, and therefore, the level of the basic tensioning of endless drive can further be reduced.However, stretcher effectively can weaken the tensioning peak value in endless drive.

Preferably, the first tension arms can be dispensed to following portion section: in the operation period of annular gear, and maximum tension occurs in this section.Thus, the large component on the first tensioning pulley of making a concerted effort can be absorbed by the bearing of the stretcher on the first pivot axis.Thus comparatively the spring force of a small amount of is enough to carry out tensioning to tension arms, therefore, can reduce the basic tensioning level of endless drive.

Advantageously, stretcher from first section be the primary importance of tightening up side to move to during second section is the second place of tightening up side and/or stretcher from second section be the second place of tightening up side move to from first section be tighten up side primary importance during, following angle keeps constant substantially: connection second pivot axis and the first spin axis line be connected the angle formed between the line of the second pivot axis and the second spin axis.Thus, only need spring works amount very in a small amount or do not need spring works amount tightening up the transition period between side and slack-side, and substantially keeping constant around the cornerite of circulation drive wheel.

Very advantageously, this angle can change be less than 10 degree and more preferably change be less than 5 degree.The amount of Angulation changes is less, and the spring works amount of needs is fewer, and cornerite keeps better.

Very advantageously, in line and the scope being connected the angle formed between the line of the second pivot axis and the second spin axis of connection second pivot axis and the first spin axis for from about 60 degree to 90 degree.Thus, power can be effectively absorbed on the tension arms tightening up side and carry out tensioning, and the fundamental component of making a concerted effort on tensioning pulley is absorbed by above-mentioned tension arms with the form of tensile force, therefore, less spring force can be applied to tension arms.

Advantageously, endless drive wheel can be a part for the apparatus assembly of annular gear, and this part has maximum inertia force square and/or maximum rotation nonuniformity.Thus, the vertical shift in endless drive can effectively be compensated.

Preferably, endless drive wheel can be a part for starter motor-generator unit.In starter motor-generator unit, during starter motor-generator unit is generator mode from starter motor patten transformation, portion's section is changed tightening up between side and slack-side, and this section is changed in slack-side and tightening up between side during starter motor-generator unit is converted to starter motor pattern from generator mode.Thus, adjoint in endless drive vertical shift is compensated with its initial point track.

Preferably, the distance of the first pivot axis and the second pivot axis can be 1/4 of the distance of the second pivot axis and the first spin axis and/or the second spin axis.Thus, stretcher disclosed herein achieves the performance characteristics being obviously different from conventional double-arm stretcher, and wherein, this double-arm stretcher comprises the tension arms arranged with V-structure, that is, comprise an only pivot axis.The reduction of the distance due to spin axis and pivot axis between---reason of the relative rotation of tension arms---, so it is enough large with the fundamental component of making a concerted effort absorbing tensioning pulley with the angle between the line being connected the second spin axis and the second pivot axis with the line of the second pivot axis to connect the first spin axis, wherein, tensioning pulley carries out tensioning by means of with being articulated and connected of the second pivot axis to tightening up side.Therefore, need less tensioned power to carry out tensioning to endless drive, that is, the basic tensioning level obviously reduced in endless drive is possible.Meanwhile, above-mentioned geometrical shape contributes to keeping good cornerite.However, stretcher effectively can weaken the tensioning peak value produced in endless drive.By means of the spacing of the first pivot axis and the second pivot axis, stretcher can compensate the vertical shift in endless drive when tightening up side and slack-side exists and changes.Therefore, this stretcher as disclosed herein makes can realize each distance between spin axis and the second pivot axis, and this is for comprising the tension arms that arranges with V-structure and being only difficult for the conventional tensioner of a pivot axis and following stretcher: this stretcher moves with effective compensation when unduly reducing cornerite or when unduly increasing the basic tensioning level of endless drive at slack-side and the vertical shift that tightens up in side transition period endless drive in the mode of substantially similar this V-type stretcher.

Advantageously, the distance of the first pivot axis and the second pivot axis can be 1/3 of the distance of the second pivot axis and the first spin axis and/or the second spin axis, is preferably at least half.Then cornerite can keep even better and can further reduce the tensioned power that two tension armss carry out needed for tensioning.Meanwhile, the vertical shift of stretcher effective compensation in endless drive.

Most preferably, Distance geometry second pivot axis of the first pivot axis and the second pivot axis and the distance of the first spin axis and/or the second spin axis greatly about the same.In this structure/layout, cornerite can be kept especially effectively, again can reduce the power of carrying out needed for tensioning to two tension armss.Meanwhile, stretcher can at the tensioning peak value tightened up in the transition period effective compensation endless drive between side and slack-side and vertical shift.

Advantageously, connect the first pivot axis and define obtuse angle with the line of the second pivot axis with the line being connected the second pivot axis and the first spin axis, preferably forming range is the angle from about 140 degree to 175 degree.Therefore, compared with the stretching, extension form of the first tension arms, the length of the second tension arms can become shorter, and the opening more greatly of angle therefore between two tension armss is possible.For the cornerite that maintenance is good, this proves favourable, and the power to two tension armss carry out needed for tensioning is reduced further.

Very advantageously, the damping bushing of the periphery/periphery along wind spring can be provided, wherein, wind spring relative to each other carries out spring loading to the first tension arms and the second tension arms, and when the diameter of wind spring changes between tension arms moving period relative to each other, wind spring is radially pressed against this damping bushing.Thus, the damping effect increasingly changed along with the change of the increasing diameter of wind spring is achieved.

Most preferably, the distance of the first pivot axis and the second pivot axis can be 1/3 of the distance of the second pivot axis and the first spin axis and/or the second spin axis, and is even more preferably at least half.

Very advantageously, Distance geometry second pivot axis of the first pivot axis and the second pivot axis and the distance of the first spin axis and/or the second spin axis greatly about the same.

Advantageously, connect the first pivot axis and define obtuse angle with the line of the second pivot axis with the line being connected the second pivot axis and the first spin axis, preferably forming range is the angle from roughly 140 degree to 175 degree.

Very advantageously, connection second pivot axis and the first spin axis line and be connected the angle formed between the line of the second pivot axis and the second spin axis scope for spend to 90 degree from roughly 60.

Most preferably, can provide the damping bushing of the periphery along wind spring, wherein, wind spring relative to each other carries out spring loading to the first tension arms and the second tension arms, and when the diameter of wind spring changes between tension arms moving period relative to each other, wind spring is radially pressed against this damping bushing.

Reference illustrates Fig. 8 of another mode of execution of stretcher 100.Stretcher 100 comprises the first tension arms 102 and the second tension arms 103.First tension arms 102 can around the first pivot axis 104 pivotable.Second tension arms 103 can around the second pivot axis 105 pivotable on the first tension arms 102.First tension arms 102 supports the first Idle wheel (such as, belt wheel 106), wherein, this first Idle wheel can rotate (by the bearing 111 shown in Fig. 9 b, axle 113 and bearing holder 115) around the first spin axis 107, and the second tension arms 103 supports the second Idle wheel (such as, belt wheel 108), wherein, the second Idle wheel can be rotated around the second spin axis 109 by bearing 117, axle 119 and bearing holder 121.

Stretcher 100 also comprises base portion 110, and this base portion 110 is mounted to regularly with the 112 (static components that Fig. 9 a) illustrates.Static component 112 can be any suitable static component, such as, such as, a part (Fig. 4) for engine cylinder-body 99.The shaft component 114 (Fig. 8) forming a part for the first tensioner arms 102 defines both the first pivot axis 104 and the second pivot axis 105.Shaft component 114 has the first axle 116, first axle 116 can by means of the lining 118 of restriction first pivot axis 104 relative to base portion 110 pivotable.Shaft component 114 also comprises the second axle 120, and this second axle 120 radially departs from the selected distance of the first axle 116.Second tensioner arms 103 is mounted to the second axle 120 pivotally to carry out the pivot movement around the second pivot axis 105.Thus, the second axle 120 defines the second pivot axis 105.

Shaft component 114 can be regarded as first of the first tensioner arms 102, first locking of this first tensioner arms 102 be connected to tensioner arms 102 with second shown in 122.It can be any applicable/suitable mode that locking connects.Such as, second stretcher arm 122 of tensioner arms 102 can be snugly but be not closely mounted to the second axle 120, and two elements 114 and 122 at the some place departed from the second axle 120 radial direction through shaft component 114 and the second stretcher arm 122, thus can keep together by locating stud 124 rotatably.Alternatively, the second stretcher arm 122 can be press-fitted into the second axle 120 enough tightly, two elements is become and locks together rotatably.

Although use term " belt wheel " for element 106 and 108 herein, it should be understood that element 106 and 108 may instead be sprocket wheel (when endless drive component 54 is chains) or engages the wheel of any other type of endless drive component of any other type.

Stretcher spring configuration

Stretcher spring 126 is positioned to the second tensioner arms 103 (with the second belt wheel 108) is biased along preferential direction (that is, the second free arm direction) relative to the first tensioner arms 102.In the mode of execution shown in Fig. 8, stretcher spring 126 is torsion springs of cylindrical shape winding, and has and be configured by the first end 128 (Fig. 9 b) that spring inserting member 130 engages the first tensioner arms 102.Spring inserting member 130 can regulate in place by threaded fastening piece 132, wherein, this threaded fastening piece 132 through the hole 134 in the first tensioner arms 102 to abut spring inserting member 130.Thus, be applied to power on spring inserting member 130 by spring 126 be passed to threaded fastening piece 132 from spring inserting member 130 and be passed to the first tensioner arms 102 from threaded fastening piece 132.By this way, the first tensioner arms 102 and spring 126 are operatively engaged with each other.Spring inserting member 130 can be made up of any applicable material such as polymeric material.Although threaded fastening piece 132 and spring inserting member 130 allow to regulate the spring force applied by spring 126, in some embodiments, threaded fastening piece 132 and spring inserting member 130 can omit.

Stretcher spring 126 also has the second end 136 of joint second tensioner arms 103.The spring coil that spring support 138 and the collar 140 can be arranged to around spring 126 near the second end 136 of spring 126.When spring 126 launch during use and radial expansion time, spring support 138 is used as damping mechanism together with the collar 140, this damping mechanism combined spring 126 and engage the surface of the first tensioner arms 102 to frictionally to frictionally.

Stretcher spring 126 is positioned to by launching each other to leave with the band opposing tension arms 102 and 103 shown in 142 in Figure 10.In this sense, stretcher spring 126 can be described to make the first arm 102 and the first belt wheel biased along the first free arm direction.When band be stretched in change in band portion section 55 and 56 time, spring 126 reels or launches until reach balance.Although the stretcher shown in Figure 10 illustrates with 100, should notice that the discussion about Figure 10 to Figure 21 is also applicable to stretcher 1.For definitely, should notice that Figure 10 to Figure 21 is intended to represent stretcher 1 and 100, but, be omitted to simplify these accompanying drawings for the specific reference character of stretcher 1.

In the mode of execution shown in Fig. 8, the first tensioner arms 102 spring biased around pivot axis 104 towards specific rotational position is not existed.Thus, during the situation making the band tensioning in one or two section 55 and 56 change, when stretcher 100 reaches equilibrium position, the first tensioner arms 102 can on demand around pivot axis 104 pivotable.

Although the torsion spring of cylindrical shape winding is shown in Fig. 8 and Fig. 9 b, the stretcher spring of other types can be used as an alternative.

Such as, in the mode of execution shown in Figure 11 a, stretcher spring can be " clockwork spring " that formed with the thread/wire usually flat by cross section shown in 148.Wire can be wound into spiral-shaped, as observable in Figure 11 a.Spring 148 can have first end (the inner) 150 and the second end (outer end) 156, wherein, shank 152, second end 156 of the groove that first end 150 has the post 154 engaging and axially extend from the second tensioner arms 103 along the first pivot axis 104 has the hook portion 158 being positioned to engage the first tensioner arms 102.Owing to using clockwork spring 148 as stretcher spring, therefore, the height (that is, extending out to the mounted distance of stretcher 100 from static component) of stretcher 100 can be less than the height of the stretcher of the use cylindrical shape winding stretcher spring 126 shown in Fig. 8.But although it should be noted that clockwork spring 148 can provide its length identical with cylindrical shape wind spring while maintenance is compared with low profile, this is to have larger diameter for cost.But neutralize the layout of the miscellaneous part around it according to the layout of the parts of stretcher 100 and vehicle motor, this is acceptable result.In stretcher, use the example of clockwork spring (although stretcher is configured to be different from the stretcher shown in Figure 11 a) to be shown in U.S. Patent No. 4,504,254 and 4,902,267, the full content of two patents is incorporated to herein.

In the mode of execution shown in Figure 11 b, stretcher spring is taper winding spring 160.Compared with cylindrical wind spring 126, the reduction that taper winding spring 160 provides height aspect also has the overall diameter less than clockwork spring 148 simultaneously.

As shown in fig. live, stretcher spring can be Linear tensioner spring 170, and this Linear tensioner spring 170 extends between arm 102 and 103, extends close between spin axis 107 and 109.Stretcher spring 170 is in tensioning state and thus by arm 102 and 103 tractive toward each other, thus urges belt wheel 106 and 108 toward each other.As illustrated in fig. 1 ld, stretcher spring can be Linear tensioner spring 170, and this Linear tensioner spring 170 extends between the contrary portion 172 of the second tensioner arms 103 and the portion 174---this portion 174 is near first arm pivot axis 104---of the first tensioner arms 102.Spring 170 is in tensioning state and thus by arm 102 and 103 tractive toward each other, thus urges belt wheel 106 and 108 toward each other.In the mode of execution shown in Figure 11 e, stretcher spring is Compress Spring 176, and this Compress Spring 176 extends and urges it and separates between the first arm 102 with the second arm 103, thus urges the first belt wheel 106 and the second belt wheel 108 toward each other.In the mode of execution shown in Figure 11 f, stretcher spring can be arc Compress Spring 178, this arc Compress Spring 178 extend between tensioner arms 102 and 103 and urge tensioner arms 102 and 103 points open, thus urge belt wheel 106 and 108 toward each other.

With reference to Figure 11 g and Figure 11 h, stretcher spring can be the form of hook spring 180, this hook spring 180 comprises Compress Spring 182 and the first constraint/wire harness portion and the second wire harness portion of constraint/wire harness portion 184, first and the second wire harness portion 184 and also can be called as in the respective end of spring 182 and the hook portion 184 that extends between the first arm and the second arm 102 and 103.Wire harness portion 184 allows Compress Spring 182 by the first arm 102 and the second arm 103 tractive toward each other.Thus, provide the effect of tension spring when not needing the specific shank of spring 182 end, tension spring needs this shank usually.Such shank represents the potential failure point in conventional tension spring.

With reference to Figure 11 i and Figure 11 j, stretcher spring can be the form of closed-cell foam spring assembly 190.Closed-cell foam spring assembly 190 comprises closed-cell foam spring 191 and traction shell 192, this traction shell 192 comprises housing 193, end member 195, towing pin 196 and space washer 197, wherein, housing 193 is formed by traction tube 194 and end member 195 is fixedly connected to traction tube 194 (such as passing through press fit).By carrying out tractive to towing pin 196 and passing through to carry out tractive to end member 195, frame set 192 acts on closed-cell foam spring 191 in the mode similar to the wire harness portion 184 in the assembly shown in Figure 11 g with Figure 11 h, makes closed-cell foam spring 191 be in compressive state and assembly 190 is in tensioning state and by the first arm 102 and the second arm 103 tractive toward each other.

Closed-cell foam spring 191 can have any suitable modification (that is, the modification in section area, shape, density and other physical properties) to provide the spring force/compression context of any needs along its length at aspect of performance.Such as, the spring rate that constant is provided in selected compression zone can be configured to.In another embodiment, can be configured to provide the spring force compensated the change of the geometrical relationship between tensioner arms and band 54, make the spring force of constant be applied to band 54, even when band 54 stretches and elongated along with time history time be also like this.Except can revising spring force/compression context, closed-cell foam spring 191 is favourable in following: can carry out a large amount of compressions relative to its resting length in some embodiments.Such as, in some embodiments, 80% (that is, closed-cell foam spring can be compressed to the length of its resting length 20%) that available amount can be its resting length is compressed.

Although be described about stretcher 100 pairs of stretcher springs, any stretcher spring in these stretcher springs can combinedly use together with stretcher 1 for replacing stretcher spring 38.The example of stretcher of---arc spiral wound spring---is shown in the open WO2007/025374A1 of PCT to comprise applicable stretcher spring.

The use of stretcher spring in the first tensioner arms

As shown in figure 12, stretcher 100 can comprise the first stretcher spring 198 acted between the first tensioner arms 102 and base portion 110.This stretcher spring 198 can be any stretcher spring in the stretcher spring shown in Figure 11 a to Figure 11 j.Stretcher spring 198 can be such as the torsion spring of spiral wound, the torsion spring of this spiral wound is positioned at the indoor in base portion 110 around axle 116, and has the first end (not shown) engaged with base portion 110 and the second end 199 engaged with the first axle 116.

Stretcher spring 198 may be used for along urging the first tensioner arms 102 towards the direction engaged with band 54.Thus, in the diagram shown in Figure 12, stretcher spring 198 can urge the first tensioner arms 102 along clockwise direction, and the stretcher spring 126 shown in Figure 12 can urge the second tensioner arms 103 in the counterclockwise direction simultaneously.

In other embodiments, stretcher spring 198 can be configured to urge the first tensioner arms 102 towards neutral position, and this neutral position can be such as the position of the tensioner arms 102 shown in Figure 12.In such mode of execution, when tensioner arms 102 moves away neutral position clockwise, stretcher spring 198 launches and is applied on arm 102 by spring force, thus urges arm 102 towards neutral position.When tensioner arms 102 moves away neutral position counterclockwise, stretcher spring 198 reels more tightly and is applied on arm 102 by spring force, thus urges arm 102 towards neutral position.

Damping structure

For stretcher 100, damping structure can not be comprised in stretcher 100.But, optionally, for suppressing the motion of the first tensioner arms 102 and the second tensioner arms 103, can damping structure be provided.Reference shows Figure 13 a to Figure 13 d of the damping structure of some types that can be included in stretcher 100.Such as, damping structure can provide in the following manner: apply substantially invariable damping force even when parts are along with being also like this when the time weares and teares, apply the damping force changed based on tensioner arms position, the angular velocity based on tensioner arms 102 or 103 and the damping force that changes is applied when tensioner arms 102 or 103 pivotable, or the moving direction applied based on tensioner arms 102 or 103 and the damping force that changes.The example of the damping structure that the wearing and tearing in damping mechanism compensate is illustrated in Figure 13 a with 200.Damping structure 200 comprises the first friction member 202, damping bias structure 204 and the second friction member 208.Second friction member 208 for providing damping surfaces on base portion 110, and it is frictionally engaged by the first friction member 202.The material of the second friction member 208 and the first friction structure 202 and these two parts be selected as providing friction factor therebetween in the surface Machining on surface that engages each other.Such as, the second friction member 208 can be made up of steel or some other nonmetallic material, and can scribble PTFE (teflon) layer etc.First friction member 202 can be made up of any applicable material, such as, such as, there is the suitable steel of suitable high-quality surface roughness.As depicted in fig. 13 a, the first friction member 202 can in the form of thrust washer, this thrust washer on the first axle 116 of shaft component 114 axially slidably but fix rotatably with the first axle.

First friction member 202 urges into and engages with the first friction member 208 by damping bias structure 204.Damping bias structure 204 can have any applicable structure.Such as, damping bias structure 204 can comprise the first taper washer 210 and the second taper washer 210.When they the first friction member 202 urged into engage with the second friction member 208 time, retaining member 206 provides following bearing surface: this bearing surface is fixing to support taper washer 210 in the axial direction relative to shaft component 118.Retaining member 206 such as can by being mounted on the end 212 of the first axle 116 with being fixed with pressure.

For suppressing the first tensioner arms 102 around the rotation of the first pivot axis 104, provide damping structure 200.When changing during band is stretched in portion's section 55 and 56 (Figure 10), second tensioner arms 103 will relative to the first tensioner arms 102 pivotable, and when tensioner arms 102 and 103 is in new equilibrium position, the first tensioner arms 102 will relative to vehicle motor pivotable.For the one in arm 102 or 103 provides damping structure 200 to contribute to suppressing the During motion of stretcher 100 when there is torsional vibration (being also referred to as " torsion ") especially in band tensioning.

When the second friction member 208 and/or the first friction member 202 wear and tear, taper washer 210 continues the first friction member 202 to urge into engage with the second friction member 208.The change of the axial length of the taper washer 210 occurred when one or two friction member in friction member 202 and 208 weares and teares is relatively little, and therefore, is applied to the spring force constant on the first friction member 202 by taper washer 210.Therefore, the frictional force between friction member 202 and 208 is approximately constant, and therefore, damping force is approximately constant.Thus, damping structure 200 can compensate the wearing and tearing in the first friction member 202 and the second friction member 208 and still keep substantially invariable damping force simultaneously.

The example applying the damping structure of the damping force changed along with tensioner arms position illustrates with 300 in Figure 13 b.Damping structure 300 comprises the first friction member 302, damping member bias structure 304 and the second friction member 308.Second friction member 308 is fixed to base portion 110, and the first friction member 302 is fixed to the first tensioner arms 102 rotatably but axially can slides relative to this first tensioner arms 102.This installation can be provided by following manner: extended internally by the flank engaged with the groove on the first axle 116 being positioned at shaft component 114 on damping member.

Second friction member 308 and the first friction member 302 have helical incline 310 and 312 respectively and distinguish joint rubbing against one another along these inclined-planes 310 and 312.These inclined-planes 310 and 312 are described further below.Helical incline 310 and 312 can have any suitable helix angle, and can the vicissitudinous helix angle of tool.Terminal stopping device optionally can be provided to the quantity limiting available pivot movement.

Biasing member 304 can be can urge friction member 302 and 308 along inclined-plane 310 and 312 towards any applicable biasing member engaged.Such as, biasing member 304 can be hollow circle tube closed-cell foam spring or spiral wound Compress Spring.When retaining member 306 first friction member 302 urged into engage with the second friction member 308 time, retaining member 306 can be fixedly connected to the first axle 116 and support biasing member 304.Retaining member 306 can comprise support member 314 and a pair locking nut 318, wherein, support member 314 is installed (such as, being threaded connection) to the end 316 of the first axle 116, and a pair locking nut 318 is mounted to end 316 in support member 314 rear threads.

When the first tensioner arms 102 and the second tensioner arms 103 are in response to the change of band tensioning during pivotable, the first tensioner arms 102 drives the first friction member 302 about the pivotable of base portion 110 rotatably relative to the second friction member 308.When the first friction member 302 rotates relative to the second friction member 308, the joint of helical incline 310 and 312 axially () drives the first friction member 302 in accompanying drawing shown in Figure 13 b up or down.The axial motion of the first friction member 302 changes the length of biasing member 304, and then change is applied to the power on the first friction member 302 by biasing member 304.This changes bias force, and then causes the change of frictional force, and therefore changes the damping force between the first friction member 302 and the second friction member 308.The increase of the band tensioning that damping structure 300 can be configured so that in band portion section 56 (Figure 10) causes the increase of the damping force between the first tensioner arms 102 and base portion 110.Alternatively, the increase of band tensioning that damping structure 300 can be configured so that in band portion section 55 (Figure 10) causes the increase of the damping force between the first tensioner arms 102 and base portion 110.Thus, damping structure 300 can be configured to provide the damping force changed in response to the angle of pivot of the first tensioner arms 102.

The example applying the damping structure of the damping force changed along with the angular velocity of tensioner arms 102 or 103 illustrates with 400 in Figure 13 c.Damping structure 400 can be configured to change damping force based on the pivotable speed of the first tensioner arms 102.Damping structure 400 can comprise the first friction member 402 and the second friction member 408.Second friction member 408 can be fixed to base portion 110 (by the rib extended radially outwardly on the second friction member 408 and the axial groove in base portion 110) rotatably.Rib and groove allow the second friction member 408 can slide relative to base portion 110.First friction member 402 installs (or fixing at least rotatably) first axle 116 to shaft component 114 regularly.Holding structure 406 can be the form of retaining member, and this retaining member is press-fitted to following position on the end 410 of the first axle 116: in this position, there is little tapered gaps between the second friction member 408 and the first friction member 402.Be provided with oiling agent 412 in the gap.Oiling agent 412 has oiling agent 412 viscosity when thixotropy makes the relative velocity between friction member 402 and 408 increase to be increased and the viscosity of oiling agent reduces when its relative velocity reduces.Therefore, when the first tensioner arms 102 pivotable quick relative to base portion 110, damping force in the first tensioner arms 102 will be larger, and when its more lentamente pivotable time, damping force will be less.

Although friction member 402 and 408 is shown in its working surface have frusto-conical, should notice that friction member 402 and 408 can have general cylindrical shape working surface as an alternative alternatively, the suitably little gap for oiling agent 412 is still arranged between friction member 402 and 408.Alternatively, friction member 402 and 408 can be the basic plane (such as, annular disk) that the selected clearance gap by wherein having oiling agent is opened.In such mode of execution, can there is multiple ring discoid first friction member 402, this first friction member 402 is connected to the first axle 116 and and is connected to that multiple ring discoids second friction member 408 of base portion 110 is staggered makes the gap with oiling agent be arranged between each first friction member 402 and each adjacent second friction member 408.

Three damping structures shown in Figure 13 a to Figure 13 c can be configured to provide " symmetry " damping, and this means the pivotal orientation not considering the first tensioner arms 102, damping force is roughly the same.Alternatively, any damping structure in three damping structures shown in Figure 13 a to Figure 13 c can be configured to provide " asymmetric " damping, and wherein, damping force is different along direction according to the first tensioner arms 102 pivotable institute.For providing such asymmetric damping, the surface of the first friction member 202,302 or 402, and/or quality process can be carried out in the following manner in the surface of friction member 208,308 or 408: when the first tensioner arms 102 along provide relatively large friction factor when the pivotable of first direction and in the rightabout pivotable of the first tensioner arms 102 along second relatively little friction factor is provided.

The substituting damping structure providing asymmetric damping illustrates with 500 in Figure 13 d.This damping structure 500 allows a large amount of vibrations in damping force for resisting tensioner arms 102 along moving with tensioner arms 102 along moving during contrary pivotal orientation pivotable during a pivotal orientation pivotable.Damping structure 500 can comprise overrunning clutch component, such as holds spring clutch spring 502 and lining 504.Lining 504 can be mounted to base portion 110 (such as, by locating stud 507) regularly and be fixedly connected to the one end (can be called for short and hold spring) held in the spirality end of spring clutch spring 502.The the second spirality end holding spring 502 can be (that is, be not fixedly attached to any object) freely, but can with the first axle 116 frictional engagement.When the first axle 116 is along first direction pivotable, the first axle 116 frictionally promotes on freely the second end holding spring 502, thus urges and hold spring 502 and launch.In a first direction, damping force is provided with the frictional engagement of the second end holding spring 502 at least in part by the first axle 116.No matter at shaft component 116 and the spring coil holding spring 502---when being forced to be depressed into expansion---between there is what frictional force, also contribute to damping force.

When the first axle 116 along second direction (namely, along and first party in the opposite direction) pivotable time, frictional engagement between first axle 116 and the second end holding spring 502 promotes the second end holding spring 502, thus makes to hold spring 502 and reel more tightly.This so cause (greatly potential) of the frictional force held between spring 502 and the first axle 116 to increase, thus to cause for resisting the high damping force of moving of the first tensioner arms 102 along second direction.Carefully can guarantee to act on damping force in the first tensioner arms 102 not making the first tensioner arms 102 during second direction pivotable locks during such pivotable.

Except above-mentioned damping force, frictional force can also be provided between thrust bearing 505 and the axial end 514 of lining 504.Frictional force can contribute to the first tensioner arms 102 along the damping force during two sense of rotation pivotables.Thrust bearing 505 is urged into by holding structure 506 and engages with lining 504, and wherein, holding structure 506 is mounted to the end 516 of the first axle 116 regularly.

Based on description above, hold spring 502 and can form/form the first friction member, and axle 116 can form the second friction member.In addition, thrust bearing 505 and lining 504 can also form the first friction member and the second friction member respectively.

Should note in some embodiments, the damping structure shown in Figure 13 a to Figure 13 d can combination with one another to form multi-functional damping structure.Such as, damping structure 400 can combine with damping structure 200 and make to there is the constant damping power do not changed with component wear and the additional damping power increased with speed.

Damping structure shown in Figure 13 a to Figure 13 d is described as the pivotable about suppression first tensioner arms 102.It should be understood that any damping structure (or any other damping structure be applicable to) in these damping structures may be used for the motion of suppression second tensioner arms 103 relative to the first tensioner arms 102.

Other damping structures can be provided, to substitute or to be additional to damping structure shown in this article.

Although illustrate the damping structure about stretcher 100 and describe, can in conjunction with any damping structure in these damping structures to use together with stretcher 1, more specifically for suppressing the first tensioner arms 102 around the motion of its pivot axis.

Figure 13 a to Figure 13 d shows the damping structure for the first tensioner arms 102.Any damping structure should noting in these damping structures alternatively or additionally can suppress the motion of the second tensioner arms 103.Such as, as shown in figure 14, similar to damping structure 200 damping structure 550 is arranged between the first tensioner arms 102 and the second tensioner arms 103 to suppress the motion of the second tensioner arms 103.Damping structure 550 comprises first friction member 552 and second friction member 554 similar with the second friction member 208 to the first friction member 202 in Figure 13 a.First friction member 552 is such as engaged by rib therebetween and groove and is fixed to the second tensioner arms 103 rotatably.Second friction member 554 can pass through any applicable device, and the rib such as between the second friction member 554 with the second axle 118 and groove engage, and are fixed to the first tensioner arms 102 rotatably.The damping bias structure 556 that can comprise the first and second taper washers 558 keeps compressive state by retainer component 560 (can be threaded io the second axle 118).First friction member 552 and the second friction member 554 urge into and are engaged with each other with selected power by the packing ring 558 of compression, this provide the damping force that opposing second tensioner arms 103 is moved relative to the first tensioner arms 102.

Any other damping structure be applicable to can additionally or alternatively be arranged between the first tensioner arms 102 and the second tensioner arms 103.The damping structure be applicable to is shown in U.S. Patent No. 4,473,362,4,698,049,6,164,091,7,273,432 and 8,142,315, open No.WO2006099731 and WO2007025374 and D.B.P. No.19524403C2 of U.S. Patent Publication No.2008/0280713, PCT, the full content of all above-mentioned patents is incorporated to herein by reference.

Short deviation distance between the pivot axis and the pivot axis of the second tensioner arms of the first tensioner arms

Distance between second pivot axis 105 and the first pivot axis 104 can be any selected distance.In the mode of execution described in Fig. 8, comparable second pivot axis 105 of distance between the first pivot axis 104 and the second pivot axis 105 and or distance between the first belt wheel spin axis 107 or the second belt wheel spin axis 109 1/4th less.In the particular implementation shown in Fig. 8, this distance can be enough short thus to deposit diametrically between the first axle 116 with the second axle 118 overlapping.In other words, the deviation distance between axle/axis 104 and 105 can be larger than the radius of axle larger in two axles 116 and 118." larger " refers to the radius of two axles in this case.The radius of the first axle 116 illustrates with R1 in fig. 8, and the diameter of the second axle 118 illustrates with R2, and the deviation distance between axle 104 and 105 illustrates with D12.Be used as in the mode of execution of stretcher spring at torsion spring 126, hub portion 127 is optionally a part for the first tensioner arms 102 and limits spring housing 129, and wherein, torsion spring 126 is positioned in spring housing 129.In this embodiment, the deviation distance D12 between axle 104 and 105 can optionally than less with the radius in the hub portion 127 shown in RH in fig. 8.

The favourable part of the stretcher 100 shown in Fig. 8 is: with the first pivot axis 104 and the distance (being also referred to as deviation distance) between 105 be the second pivot axis 105 with 1/4 of the first belt wheel spin axis 107 and 109 distances between the two stretcher compare, allow stretcher 100 relative compact (and therefore relatively light).Thus, stretcher 100 may be used for the motor relatively more small-sized than stretchers more of the prior art.In addition, the swinging distance that following stretcher advances can be less than: this stretcher has the deviation distance larger than 1/4th of the second pivot axis and the first and second belt shafts distance between the two by the swinging distance providing following stretcher 100, first tensioner arms 102 to advance during pivot movement.

Tensioner arms structure relative to each other

In the mode of execution shown in Figure 10, first arm 102 (namely, principal arm) and the second arm 103 (that is, auxiliary) be arranged so that on principal arm 102 belt wheel 106 and guide in the counterclockwise direction around the first pivot axis 104 on second auxiliary 103 belt wheel 108.Therefore, the stretcher 100 shown in Figure 10 can be called as counterclockwise guiding/leading configuration.Show principal arm 102 with reference to Figure 15, Figure 15 and guide the stretcher 100 of the second arm 103 in the counterclockwise direction and stretcher 100 thus in Figure 15 can be called as and has clockwise guiding/leading configuration.Stretcher 100 is meant to as what guide clockwise or guide counterclockwise the moving direction can not considering band 54.Such as, 54 are with can to move in a clockwise direction along its path in the diagram shown in Figure 10 and Figure 15.For the purpose of clearer, term used herein guides clockwise and guides counterclockwise is make from some from the visual angle of the outside of motor viewing stretcher 100, and in motor, sees stretcher 100 is contrary.

To the restriction of the range of movement of the first and/or second tensioner arms

For limit the first tensioner arms 102 relative to the range of movement of engine cylinder-body 99 and for restriction second tensioner arms 103 relative to the range of movement of the first tensioner arms 102, can limiting structure be provided.The limiting structure of any applicable mode can be provided.Such as, as shown in figure 16, limiting structure is arranged with the form of protuberance 700 in the first tensioner arms 102, and it extends in the groove 702 in the second tensioner arms 103.Protuberance 700 has the first limiting surface 704 and 706 thereon, and this first limiting surface 704 and 706 is bonded on the second limiting surface 708 and 710 of the end of groove 702 respectively.

With reference to Figure 17, the limiting structure (can be mounted to engine cylinder-body 99 regularly by the element 112 shown in Fig. 9 a) between the first tensioner arms 102 and base portion 110 is formed by the protuberance 712 in the first tensioner arms 102---the groove 714 in this protuberance 712 engagement base 110.The first limiting surface 716 (only a surface 716 is shown in Figure 17 because of other surface 716 cresteds in shown accompanying drawing) on the end of protuberance 712 can engage with the second limiting surface 718 of the end of groove 714 to limit the first tensioner arms 102 relative to base portion 110 and thus relative to the range of movement of engine cylinder-body 99 (only a surface 718 is shown in Figure 17 because of other surface 718 cresteds in shown accompanying drawing).Although limiting surface is depicted as the two ends of the angular region of the two ends of the motion angular region for limiting the first tensioner arms 102 and the motion of the second tensioner arms 103, but be understood that and can provide single first limiting surface and single second limiting surface as an alternative, to provide the restriction of only one end of the range of movement to the first tensioner arms 102 or the second tensioner arms 103.

Although limiting structure can provide with the form of the protuberance in the groove shown in Figure 16 and Figure 17, but the limiting structure of other types can be provided alternatively, such as, such as, by holding the mode of spring clutch, this holds the rotating amount that spring clutch is selected from original position winding or allow before being expanded to working position at it, so hold spring clutch to engage following engaging surface: this engaging surface prevents any motion be associated with tensioner arms further.Such as, the first tensioner arms 102 can be locked to base portion 110 by limiting structure, thus prevents the first tensioner arms 102 moving further along preferential direction.If the first tensioner arms 102 is urged the position engaged from clutch in opposite direction and returns, then clutch can be disengaged thus allow the first tensioner arms 102 motion in opposite direction.Thus, in this example, the limiting structure that spring clutch and the engaging surface that is bonded together are construed as limiting the range of movement of the first tensioner arms 102 (along a direction) is held.

Alternatively, variable damping structure can be arranged in one or all two tensioner arms in tensioner arms 102 and 103, and adaptive damping structure provides the damping force changed along with the position of any one tensioner arms associated therewith in tensioner arms 102 or 103.Variable damping structure can be configured so that damping force is increased to and prevent from being with tensioning to make the degree of tensioner arms 102 and/or 103 movement.

Alternatively, ball retainer or pin can be positioned at select location with adjacent tensioner arms 102 and/or 103 and limit its range of movement.Alternatively, the structure that any other is applicable to can be provided.

Additional idle pulley/lazy belt wheel in first tensioner arms and the second tensioner arms

Except provide there is belt wheel 106 and 108 thereon respectively the first tensioner arms 102 and the second tensioner arms 103 except, stretcher 100 can also comprise one or more additional idle pulley thereon.Example is illustrated in Figure 18, and wherein, idle pulley 800 is depicted as and is mounted to the first tensioner arms 102 and rotates for the pivot axis 105 around the second tensioner arms, and engages with the 3rd section 59 of band 54.Idle pulley 800 can have some effects to the helper drive band 54 engaged.Such as, idle pulley 800 makes the band amount of holding existed around crankshaft pulley 51 increase.Usually, when band is advanced around auxiliary/accessory drive system, the addition bend that band introduced by belt wheel is increased.In addition, the belt wheel of increase represents the additional source of pivot friction.All these effects can cause the increase of the power consumpiton (that is, additional/parasitic loss) be associated with accessory drive system.But by increasing about the amount held of crankshaft pulley 51, the band tensioning in band can occur to reduce when be with the possibility of skidding with crankshaft pulley when not increasing, the energy of this reduction driving required for accessory drive system.In some embodiments, energy-conservation more for compensating the increase with the bending energy ezpenditure be associated of additional bearing friction and band by what be with the reduction of tensioning to provide.Therefore, in some embodiments, idle pulley 800 is provided can to cause the clean minimizing of the supplementary loss be associated with accessory drive system as the part of stretcher 100.

Another effect of idle pulley can be change the responsiveness of stretcher 100 when changed by band tensioning.Usually, observed compared with the example of the belt tightener 100 not having idle pulley 800, the stretcher 100 with the idle pulley 800 installed around axle/axis 105 makes the response of stretcher 100 accelerate with the self-control when suffering the change of being with tensioning.This is because drive the generation of any change of the band tensioning of the pivotable of the first tensioner arms 102 can also produce moment through idle pulley 800 in the first tensioner arms 102, this moment is by being applied to moment in the first tensioner arms 102 and additional by the band 54 acted on the first belt wheel 106.If be specifically apply the fast response time or large response that need for the change of band tensioning, so may need to add the idle pulley 800 around pivot axis 105.When idle pulley 800 is located in the mode of the response accelerating stretcher 100, idle pulley 800 can be called as starter belt wheel.

Except by the idle pulley 800 of interpolation except the second pivot axis 105 is located, idle pulley 800 can be located around idle pulley pivot axis 802 alternatively, wherein, this idle pulley pivot axis 802 is on the opposition side of the first pivot axis 104 to the first tensioner arms belt wheel spin axis 107.In the position shown in Figure 19, idle pulley 800 can increase the amount that holds of band that flexing shaft pulley 51 is arranged, although be less than the amount that the band when idle pulley 800 is installed around the second pivot axis 105 holds.But the band of increase holds the abundant minimizing that can cause band tensioning, thus exist with as in Figure 19 the idle pulley 800 of locating be associated only energy-conservation.Observe, when idle pulley 800 is located around the idle pulley pivot axis 802 on the opposition side of the first pivot axis 104 to the first tensioner arms belt shaft 106, compared with the example of the stretcher 100 of additional idle pulley 800, the responsiveness of stretcher 100 when changed by band tensioning reduces.This is because drive the generation of any change of the band tensioning of the first tensioner arms 102 pivotable also to produce the moment of passing idle pulley 800 in the first tensioner arms 102, this moment is contrary with the moment be applied in the first tensioner arms 102 by the band 54 acted on the first belt wheel 106.

In some embodiments, exist and be passed to the vibration force of stretcher 100, thus make to engage between the belt wheel 108 on the opposite side of the belt wheel 106 on the side of alternator or SGU belt wheel 52 and alternator or SGU belt wheel 52.---idle pulley 800 is positioned on the opposition side of the first pivot axis 104 to belt wheel 106 thus---can contribute to stretcher 100 and resist motion because of vibration force to provide idle pulley 800 as shown in figure 20.Be in its idle pulley 800 reduced in the position of the responsiveness of stretcher 100 and can be called as stabilizer belt wheel.

As another replacement scheme, belt wheel 800 can be located around the first pivot axis 104, as shown in Figure 20.In the position shown in Figure 20, idle pulley 800 can increase the amount that holds of band that flexing shaft pulley 51 is arranged, although be less than the amount that the band when idle pulley 800 is installed around the second pivot axis 105 holds.But the band of increase holds the abundant minimizing that can cause band tensioning, thus exist with as in Figure 20 the idle pulley 800 of locating be associated only energy-conservation.Observe, when idle pulley 800 is located around the first pivot axis 104, with do not have idle pulley 800 stretcher 100 example compared with, the responsiveness of stretcher 100 does not change when changed by band tensioning.This is because thus any power introduced by belt wheel 800 do not apply moment through the first pivot axis 104 in the first tensioner arms 102.

Usually, the idle pulley 800 providing the band increasing flexing shaft pulley 51 to hold is favourable, is particularly conducive to there is the application of band in the risk of the increase of crankshaft pulley 51 skidding.Such as, in following application, wherein, SGU16 is used as BAS (band-alternator-starting) transmission system and thus for making crankshaft pulley 51 rotate and pilot engine by band 54, there is the risk of the increase that band skids at crankshaft pulley 51 place during such engine start.By providing idle pulley 800, the generation with skidding during the band of the increase of flexing shaft pulley 51 holds the engine start suppressing such, and the very high band tensioning in band 54 need not be relied on.Thus, the stretcher 100 and stretcher 100 particularly with one or more idle pulley 800 can allow vehicle to have does not have the BAS transmission system of very high-band tensioning.BAS transmission system by provide stop-start ability can contribute to some vehicles make vehicle can temporary transient static time (such as at stop light place) close and reset when needed.Although this can save energy, but some BAS transmission systems need accessory drive system with the band tensioning operation improved like this, thus the increase of the energy-conservation supplementary loss by being associated with the band tensioning increased of at least some provided by stop-start ability and offsetting.The stretcher 100 particularly having idle pulley 800 by providing stretcher 100, the band of flexing shaft pulley 51 holds the risk that can be made it possible to provide by adjustment the low band tensioning still control cincture skidding when SGU is for piloting engine by band 54 simultaneously.Therefore, what can realize being associated with BAS transmission system is more energy-conservation.

The position that the band that although idle pulley 800 is illustrated in increases flexing shaft pulley 51 (with auxiliary belt wheel 53) holds, idle pulley 800 can be arranged to the band increased around some other auxiliary member/annexes (in the accessory drive system comprising more auxiliary member in than accompanying drawing shown in this paper) and hold.

Although illustrate only single additional idle pulley 800, except idle pulley 800 and belt wheel 106 and 108, other additional idle pulley can also be provided alternatively.Additional belt wheel like this may be used for increasing and holds around auxiliary belt wheel or for the band of some other reasonses.

Except the band increasing strip winding wheel holds to prevent from, except band skidding, because of other reasons, providing idle pulley such as belt wheel 800 also can be favourable.Such as, can find out that from the contrast of Figure 15 and Figure 18 idle pulley 800 changes the direction (that is, hub load vector) of the hub load of belt wheel 51 and 53, and the hub load at other belt wheel places can be affected.The hub load at belt wheel 51 place is depicted as vector F 51, and the hub load at belt wheel 53 place is depicted as vector F 53.These hub loads are examples of hub load during the situation of crankshaft pulley 51 rotating band 54.

The hub load providing another advantage of idle pulley 800 to be on idle pulley 800 can offset the hub load on belt wheel 106 and 108 at least in part, makes the clean hub load at the first pivot axis 104 place can be less than load in the example of the stretcher 100 not having idle pulley 800.Thus, idle pulley 800 may be used for the hub load at pivot axis 104 place of minimizing first tensioner arms 102.

For the idle pulley used together with second is with

Belt wheel 800,106,108,51,52 and 53 is all described for splicing tpae 54.In the mode of execution of Figure 21, accessory drive system can also be included in the second band 850 in the second band plane, and this second band plane is the band plane of the first band plane being different from band 54 movement.Second band 850 drives by installing the second crankshaft pulley 852 being used for jointly rotating with the first crankshaft pulley 51.One or more auxiliary belt wheel is driven by the second band 850.In the example shown, two auxiliary belt wheels 854 and 856 are shown.Auxiliary belt wheel 854 can be the belt wheel from any applicable auxiliary member, such as, the belt wheel of such as vacuum pump, compressor, power conveying device or any other auxiliary member be applicable to.

In embodiments, can provide idle pulley 856 in the first tensioner arms 102, this idle pulley 856 is positioned in splicing tpae 850 in the second band plane.Belt wheel 856 can be arranged on belt wheel 854 and 852 and provide the selected band amount of holding, or for eliminating the object of large band span, this large band span otherwise exists and represents to exist makes band tremble the risk occurred.

The first pivot axis 104 that idle pulley 856 can be positioned at stretcher 100 is sentenced and is made it also be even like this when the change of the band tensioning in band 54 causes the pivot movement of the first tensioner arms 102 and the second tensioner arms 103 by remaining on constant position.

Additional design

Although shown stretcher 1 and 100 to comprise the first tensioner arms 2,102 and second tensioner arms 3,103, additional tensioner arms can also be increased.In other words, stretcher 1 or 100 can comprise three tensioner arms, thus, such as, exist and there is first tensioner arms being mounted to engine cylinder-body pivotally of the belt wheel similar to arm 2 or 102, there is second arm being mounted to the first arm pivotally of the belt wheel similar to arm 3 or 103, and there is the 3rd arm being mounted to the first arm (or being mounted to the second arm alternatively) pivotally of the 3rd belt wheel thereon.3rd arm can be positioned at any suitable place, such as such as, the position of splicing tpae portion section between crankshaft pulley 51 and belt wheel 53, replaces and use idle pulley 800.

For tensioner arms 103, " under belt wheel " configuration is shown, belt wheel 108 is positioned between arm 102 and engine cylinder-body 99 thus, and tensioner arms 102 is depicted as " on belt wheel " configuration, and thus, tensioner arms 102 is between belt wheel 106 and engine cylinder-body 99.It should be understood that stretcher 1 or 100 can to have on belt wheel and under belt wheel tensioner arms any suitable combination and to illustrate and the configuration that describes is not intended to be limited.

The concise and to the point description of the example of the advantage of Y type stretcher design contrast V-type stretcher

Although the advantage of stretcher 1 and 100 can be clearly according to description above and accompanying drawing, but for the purpose of clearer, its summary of benefits is as follows: the advantage of the stretcher 1 and 100 illustrating herein and describe provides some advantages being better than V-type stretcher (that is, having single pivot axis, the first tensioner arms and the second tensioner arms relative to the stretcher of engine cylinder-body around this pivot axis).When using stretcher 1 or 100 to carry out tensioning to band 54, from stretcher spring (namely second tensioner arms 3 or 103 can be configured so that band portion section 55 or 56---belt wheel 108 can engage against this band portion section 55 or 56---can pass through, spring 126) the relatively little spring force that needs is to keep tensioning, because the second arm 3 or 103 can be configured with the relatively little angle relative to being present in belt wheel 108 place and carrying the hub load of 54.By contrast, when the first tensioner arms is identical with the pivoting point of the second tensioner arms (the same with the situation of V-type stretcher), there is less flexibility and the second tensioner arms can be large angle relative to the hub load be applied on its belt wheel when selecting the pivoting point about the second tensioner arms.Therefore, relatively large spring force can be needed to produce the band tensioning from the second tensioner arms in V-type stretcher.Large spring force can force V-type stretcher relative to the increase of stretcher 1 or 100 in size, weight and cost.

What one skilled in the art should appreciate that is can carry out various amendment when not departing from the reasonable sense of claims to mode of execution described herein.

Claims

1. a stretcher, comprising:

First tensioner arms and the second tensioner arms, wherein, described first tensioner arms can around the first pivot axis, and described second tensioner arms is pivotally connected to described first tensioner arms thus can around the second pivot axis leaving described first pivot axis location with selected distance; And

The first round and second takes turns, the described first round is connected to described first tensioner arms rotatably around the first spin axis, and described second takes turns and be connected to described second tensioner arms rotatably around the second spin axis, wherein, the described first round becomes engagement annular dirivig member with described second wheel construction

Wherein, the described first round and described second takes turns and is biased along corresponding first free arm direction and the second free arm direction.

2. stretcher according to claim 1, wherein, the distance between described first pivot axis and described second pivot axis is less than 1/4th of the distance between at least one in described first spin axis and described second spin axis and described second pivot axis.

3. stretcher according to claim 1, also comprises biasing member, and described biasing member to be connected between described first tensioner arms and described second tensioner arms thus described first tensioner arms and described second tensioner arms are biased toward each other.

4. stretcher according to claim 1, also comprises winding torsion spring, and described winding torsion spring is positioned to described second tensioner arms is biased towards second section of described endless drive component,

Wherein, at least one in described first tensioner arms and described second tensioner arms comprises the hub portion limiting spring housing at least in part, and wherein, described winding torsion spring is positioned in described spring housing, and

Wherein, the described selected distance between described first pivot axis and described second pivot axis is less than the radius in described hub portion.

5. stretcher according to claim 1, also comprises winding torsion spring, and described winding torsion spring is positioned to described second tensioner arms is biased towards second section of described endless drive component,

Wherein, the described selected distance between described first pivot axis and described second pivot axis is less than the radius of described wind spring.

6. stretcher according to claim 1, also comprises: the first arm biasing member, and described first arm biasing member is positioned to make described first tensioner arms biased along described first free arm direction; With the second arm biasing member, described second arm biasing member is positioned to make described second tensioner arms biased along described second free arm direction.

7. stretcher according to claim 1, also comprises damping structure, and described damping structure is configured to apply resistance to the motion of the tensioner arms of in described tensioner arms.

8. stretcher according to claim 7, wherein, described damping structure based on the described tensioner arms in described tensioner arms position and change the described resistance of the described tensioner arms be applied in described tensioner arms.

9. stretcher according to claim 7, wherein, described damping structure based on the described tensioner arms in described tensioner arms rotational speed and change the described resistance of the described tensioner arms be applied in described tensioner arms.

10. stretcher according to claim 7, wherein, described damping structure based on the described tensioner arms in described tensioner arms direct of travel and change the described resistance of the described tensioner arms be applied in described tensioner arms.

11. stretchers according to claim 7, wherein, described damping structure is configured to apply following resistance: this resistance is based on the rotational speed of the described tensioner arms in described tensioner arms and the described tensioner arms be applied in described tensioner arms.

12. stretchers according to claim 7, wherein, described damping structure comprises the first friction member, the second friction member urges into described second friction member the damping structure bias structure be engaged with each other with by described first friction member.

13. stretchers according to claim 1, also comprise idle pulley, and described idle pulley is rotatably connected to the one in described first tensioner arms and described second tensioner arms, and described idle pulley is positioned to engage described endless drive component.

14. stretchers according to claim 13, wherein, described idle pulley is rotatably connected to described first tensioner arms to rotate around described first pivot axis.

15. stretchers according to claim 13, wherein, described idle pulley is connected to described first tensioner arms in the mode that can rotate around idle pulley spin axis, and wherein, described first pivot axis is roughly positioned between described idle pulley spin axis and described second pivot axis.

16. stretchers according to claim 13, wherein, described idle pulley is connected to described first tensioner arms in the mode that can rotate around idle pulley spin axis, and wherein, described second pivot axis and described idle pulley spin axis are positioned at the same side of described first pivot axis.

17. 1 kinds, for the annular gear of explosive motor, comprising:

Annex, described annex has the rotor being connected to annex wheel;

Endless drive component, described endless drive component partly holds described annex wheel and the crank wheel partly held on the bent axle being positioned at described explosive motor; And

Stretcher, described stretcher comprises:

First tensioner arms and the second tensioner arms, wherein, described first tensioner arms can around the first pivot axis, and described second tensioner arms is pivotally connected to described first tensioner arms thus can around the second pivot axis leaving described first pivot axis location with selected distance;

The first round, the described first round is connected to described first tensioner arms rotatably around the first spin axis, and the described first round is resisted against first section of described endless drive component thus makes the tensioning of described endless drive component; And

Second takes turns, and described second takes turns and be connected to described second tensioner arms rotatably around the second spin axis, and described second takes turns second section being resisted against described endless drive component thus make the tensioning of described endless drive component,

Wherein, the described first round and described second takes turns all to be biased to and engages to corresponding described first section of described endless drive component and described second section.

18. annular gear according to claim 17, wherein, described annex is starter motor-generator unit, and wherein, and first section of described endless drive component and second section have the end at the wheel place being positioned at described starter motor-generator unit separately.

19. annular gear according to claim 18, wherein, when described crank wheel drives described endless drive component, second section of described endless drive component bears larger tensioning than first section of described endless drive component, and when described starter motor-generator unit drives described endless drive component, first section of described endless drive component bears larger tensioning than second section of described endless drive component.

20. annular gear according to claim 17, wherein, when towards described annular gear on described explosive motor, the described first round takes turns spaced apart in described second front of taking turns and described second around described first pivot axis in the clockwise direction.

21. annular gear according to claim 17, wherein, when towards described annular gear on described explosive motor, the described first round takes turns spaced apart in described second front of taking turns and described second around described first pivot axis in the counterclockwise direction.

22. annular gear according to claim 17, also comprise idle pulley, described idle pulley is rotatably connected to the one in described first tensioner arms and described second tensioner arms, and described idle pulley engages the 3rd section of described endless drive component.

23. annular gear according to claim 22, wherein, described idle pulley is rotatably connected to described first tensioner arms to rotate around described first pivot axis.

24. annular gear according to claim 22, wherein, described idle pulley is connected to described first tensioner arms in the mode that can rotate around idle pulley spin axis, and wherein, described first pivot axis is roughly positioned between described idle pulley spin axis and described second pivot axis.

25. annular gear according to claim 22, wherein, described idle pulley is connected to described first tensioner arms in the mode that can rotate around idle pulley spin axis, and wherein, described second pivot axis and described idle pulley spin axis are positioned at the same side of described first pivot axis.

26. annular gear according to claim 22, wherein, described idle pulley is taken turns antarafacial location relative to the described first round and described second and is engaged the second endless drive component, and described second endless drive component takes turns extension around the multiple of optional feature.